Method of distilling hydrocarbons



Aug. 14. 1928. 1 680380 F. E. WELLMAN METHOD OF DISTILLING HYDROCARBONS Filed J-une 1922 Patented 14, 1928 UNITED STATES PATENT OFFICE.1

Imam-n or mnsns'crry, KANSAS, nssrenon 'ro KANSAS cm Gaso- LINE comm, or knnsns our, KANSAS, A coaronnrron or KANSAS.

mn'rnon or ms'rrrnmo nrnnocmons v Application filed June 3,

- My invention relates to the treatment of hydro-carbon oils, and has special reference to cracking petroleum. It has for its objects the; improvement of the-methods heretoi'ore practiced in treating the heavier fractions which are ordinarily separated out and refluxed to the cracking still for re-treatinent to produce an increased-yield of gasoline with a minimum amount of fuel consumed, and to positively control the fractions finally delivered to the condenser.-

Heretofore" the return of condensate to the cracking still has been carried on by direct and simultaneous cooling and running back of the condensedfraction-s. According to my present invention, however, the

return is not direct nor simultaneous with the cooling, but the heavy fractions separated out are treated in a supplemental still, and after distilling off their lighter components are then returned to the cracking still for re-cracking. The e erationis a consure, 01 under PIBSSUIG not excee tionator 3, .having a leading tinuous one, fresh oil being fed in by way of the supplemental still, and the lighter vapors from both the cracking still an the supplemental still being carried through a ipe line containing a pressure retaining va ve, to the" condenser, where they are finally condensed either at atmos heric presin'g twenty pounds per square inch.v

The accompanying drawing is a d agram illustrating one form of' apparatus w1th which my invention ma be practiced.

In the drawing, 1 in icates the cracking stili,'2 the vapor line tfheriefrom to the fracline 10, and a down p1pe 4 into the supple-- mental still 5,'which is connected by vapor line 9 to a supplemental ffractionator 6 also connected to the vapor line 10' and thence to a pipe line 12 containing a valve 11 and to the condenser 13 fromwhich suitable connection is effected to the storage 'tank 14. Stills 1 and 5 are heatedby furnaces 1" and 5, respectively.

In operation, the cracking still, being filled with hydrocarbon oil to the level marked'lfi, is heated to approximately 7 F., whereupon vapors pass through the line 2 to the fractionator 3, wherein cooling and condensation of. the heavier fractions take place, the lighter va ors assing over and into pipe line 1 0 he eavy condensate is thrown down and drains through pipe pipe 8, -a vapor 1922. Serial No. 56,634.

filledto common liquid level 15, maintained through the pipe 7. I Heat is applied to the supplemental still 5 and the oil therein is re-distilled at a proximately 550 F., the

4 into the supplemental still 5, which is I valve 11, The vapors are then released through valve 11 and pass through pipe line 12to the condenser, where they are all con densed under pressure of twenty pounds or less. The process is rendered continuous by supplying fresh oil through supply pipe 8, as the level 15 is lowered by withdrawals.

The advantages attained by the; intro-' duction of supplemental heating thusdescribed, will be obvious tothose skilled in ,the art.- In the previous systems referred to, in which simultaneous cooling and refiuxing are carried on, rising .vapors are I constantly carrying and giving'up heat to.

the temperatures of the two counter flowing streams.

My system on'the other hand attains the following pronounced and useful results:

1. Heat is applied to the condensate be'-. fore its return to the cracking-still, under control of an operator, and its tem erature can therefore, be regulated wit in the necessary limits ,to secure desired fractions in thelcondenser. --This cannot be done with ordinary refluxing. 2. 'lihe vaporization due to such supplementa heatingtakes place away from and out'of contact with the vapor stream from the cracking still, whereby adulterationis avoided. Such adulteration or mixing of high and low boiling fractions in the vapor line always takes place where the reflux is through said line. y j 3. The operation of supplemental still 5 results in-an increased yield of gasoline, because all the material that'reaches the condenser is within the proper boiling range,

the condensed and condensing material 211- instead of only former practice.

I am aware that some changes may be made in the apparatus and detailed'operw tion thus described; and I wish it understood that I contemplate all such changes as fall fairly within the scope of the appended claims.

What I claim is:

1. The method of treating hydrocarbon oil to produce a lighter hydrocarbon of the same series, which consists in distilling the heavier hydrocarbon in one zone at high cracking temperature and pressure, fractionating all the vapors produced in said first zone in a second zone, conducting olf and condensing the vapors from said second or fractionating zone while refluxing to and redistilling the heavier fractions in a third zone at a temperature lower than that in the first cracking zone, separately fractionating in a fourth zone the vapors produced by redistillation in said third zone, conducting a fraction thereof as by off and condensing the light vapors from' said fourth zone, returning the heavier fractions from the fourth zone into the third zone, and returning all the heavier fractions from the third zone in liquid phase into the first zone.

2. The method of treating hydrocarbon oil to produce a lighter hydrocarbon of-the same series, which consists in distilling the heavier hydrocarbon in one zone at high cracking temperature and pressure, fractionating all the va ors produced in said first zone in a secon zone, conductingoff and condensin the vapors from said second or fractionatmg zone while refluxing to and redistilling the heavier fractions in a third zone at a temperature lower than that in the first crackin zone, separately fractionating in a fourt zone the vapors produced by redistillation in said third zone, conducting off and condensing the light vapors from said fourth zone, returning the heavier fractions from the fourth zone into the third zone, and returning all the heavier fractions from the third zone in liquid phase into the first zone, by gravity, the pressure in both the flirst and third zones being maintained equa 3. The method of treating hydrocarbon oil to produce a lighter hydrocarbon of the same series, which consists in distilling the heavier hydrocarbon in one zone at high cracking temperature and pressure, fractionating all the vapors produced in said'first zone in a second zone, conducting off and condensing the vapors from said second or fractionating zone while refluxing to and redistilling the heavier fractions in a third zone at a temperature lower than that in the first cracking zone, separately fractionating in a fourth zone the vapors produced by redistillation in said third zone, conducting off and condensing the light vapors from said fourth zone, returning the heavier fractions from the fourth zone into the third zone, and returning all the heavier fractions from the third zone in liquid hase into the first zone while introducing i resh oil to replace the portions distilled off, through the second zone, into the third zone and thence into the first zone.

In testimony whereof I hereunto ailix my 18 signature.

FRANK E. WELLMAN. 

